Flexible, printed electronics is a revolutionary new concept for fabricating optoelectronic devices using high-throughput, inexpensive solution processes (e.g., printing methodologies) on flexible plastic foils, which contrasts sharply with the highly specialized and expensive facilities and equipment required for silicon fabrication. By developing new electronic materials, these technologies can enable inexpensive, lightweight, flexible, optically transparent, and unbreakable components for a wide variety of applications such as displays, cell phones, medical diagnostics, RFID tags, and solar modules, which then can be integrated with textiles, printed batteries, solar cells, aircraft or satellite structures, and the like. The enabling material component of all these technologies (among other essential materials) is the semiconductor where charge transport, light absorption, and/or light generation occur. To broaden device functionalities and applications, two types of semiconductors are required: p-type (hole-transporting) and n-type (electron-transporting). The use and combination of these two types of semiconductors enable the fabrication of elementary electronic building blocks for driving displays, harvesting light, generating light, carrying out logic operations, and sensor functions. To enable high device efficiencies such as large charge carrier mobilities (μ) needed for transistor/circuit operations, or efficient exciton formation/splitting necessary for photonic devices, organic semiconductors should have an appropriate electronic structure to favor specific functions.
Several p- and n-channel molecular semiconductors have achieved acceptable device performance and stability. For example, OTFTs based on acenes and oligothiophenes (p-channel) and perylenes (n-channel) have reported carrier mobilities (μ's)>1 cm2/Vs in ambient conditions. However, molecular semiconductors typically are less easily processable via printing methodologies than polymeric semiconductors due to solution viscosity requirements.
Accordingly, the art desires new molecular and polymeric semiconducting compounds, particularly those having good stability, processing properties, and/or charge transport characteristics in ambient conditions.